willdurand / taskgraph

Generates task dependency graphs for Taskcluster CI

Taskgraph

Taskgraph is a Python library to generate graphs of tasks for the Taskcluster CI service. It is the recommended approach for configuring tasks once your project outgrows a single .taskcluster.yml file and is what powers the over 30,000 tasks and counting that make up Firefox's CI.

For more information and usage instructions, see the docs.

How It Works

Taskgraph leverages the fact that Taskcluster is a generic task execution platform. This means that tasks can be scheduled via its comprehensive API, and aren't limited to being triggered in response to supported events.

Taskgraph leverages this execution platform to allow CI systems to scale to any size or complexity.

1. A decision task is created via Taskcluster's normal .taskcluster.yml file. This task invokes taskgraph.
2. Taskgraph evaluates a series of yaml based task definitions (similar to those other CI offerings provide).
3. Taskgraph applies transforms on top of these task definitions. Transforms are Python functions that can programmatically alter or even clone a task definition.
4. Taskgraph applies some optional optimization logic to remove unnecessary tasks.
5. Taskgraph submits the resulting task graph to Taskcluster via its API.

Taskgraph's combination of declarative task configuration combined with programmatic alteration are what allow it to support CI systems of any scale. Taskgraph is the library that powers the 30,000+ tasks making up Firefox's CI.

Installation

Taskgraph supports Python 3.6 and up, and can be installed from Pypi:

pip install taskcluster-taskgraph

Alternatively, the repo can be cloned and installed directly:

git clone https://github.com/taskcluster/taskgraph
cd taskgraph
python setup.py install

In both cases, it's recommended to use a Python virtual environment.

Get Involved

If you'd like to get involved, please see our contributing docs!